Switching system for a transportation system employing a guideway

ABSTRACT

A switching system for a transportation system of the type employing a guideway and vehicles adapted to travel along the guideway. A guideway junction is provided having a first end communicating with a first portion of the guideway and having a bifurcated, second end communicating with second and third, mutually diverging portions of the guideway. A movable guide rail is positioned adjacent the first end of the junction and pivotable between first and second positions for initially guiding a vehicle in a respective one of two directions upon the vehicle entering the junction from the junction first end. A fixed, guiding means is positioned between the movable guide rail and the second guideway portion and is operable to guide a vehicle through the junction and onto the second guideway portion upon the vehicle being initially guided by the movable guide rail while the movable guide rail is in its first position; and another fixed, guiding means is operable to guide a vehicle through the junction and onto the third guideway portion upon the vehicle being initially guided by the movable guide rail positioned in its second position. In one embodiment of the switching system, the movable guide rail is positioned by actuating means operable for moving the guide rail to a selected one of its two positions. In another embodiment adapted particularly to accomodate vehicles entering the junction from the second or third guideway portions, the movable guide rail is normally held in its first position by positioning means operable for resiliently urging the movable guide rail to its first position, and is deflected to its second position by vehicles which enter the junction from the third guideway portion.

United States Patent [191 Metcalt Jan.1,]1974 SWITCHING SYSTEM FOR A TRANSPORTATION SYSTEM EMPLOYING A GUIDEWAY John M. Metcalf, Dallas, Tex.

[73] Assignee: LTV Aerospace Corporation, Dallas,

Tex.

22 Filed: Nov. 29, 1971 21 Appl.No.:202,753

[75] Inventor:

[56] References Cited UNITED STATES PATENTS 3,098,454 7/1963 Maestrelli 104/130 1,690,448 ll/l928 Hornby 246/388 3,650,216 3/1972 Broome 104/130 3,456,596 7/1969 Cooper .1 104/100 3,680,488 8/1972 Donlon 104/130 3,403,634 l0/1968 Crowder 104/84 3,310,004 3/1967 Chandenson 104/130 Primary Examiner-Gerald M. Forlenza Assistant E.\'aminerD. W. Keen Attorney-James M. Cate et a1.

[57] ABSTRACT A switching system for a transportation system of the type employing a guideway and vehicles adapted to travel along the guideway. A guideway junction is provided having a first end communicating with a first portion of the guideway and having a bifurcated, second end communicating with second and third, mutually diverging portions of the guideway. A movable guide rail is positioned adjacent the first end of the junction and pivotable between first and second positions for initially guiding a vehicle in a respective one of two directions upon the vehicle entering the junction from the junction first end. A fixed, guiding means is positioned between the movable guide rail and the second guideway portion and is operable to guide a vehicle through the junction and onto the second guideway portion upon the vehicle being initially guided by the movable guide rail while the movable guide rail is in its first position; and another fixed, guiding means is operable to guide a vehicle through the junction and onto the third guideway portion upon the vehicle being initially guided by the movable guide rail positioned in its second position. In one embodiment of the switching system, the movable guide rail is positioned by actuating means operable for moving the guide rail to a selected one of its two positions. In

another embodiment adapted particularly to accomo- I date vehicles entering the junction from the second or third guideway portions, the movable guide rail is normally held in its first position by positioning means operable for resiliently urging the movable guide rail to its first position, and is deflected-to its second position by vehicles which enter the junction from the third guideway portion.

30- Claims, 22 Drawing Figures PATENTED 1 4 saw 02 or 10 PATENTED JAN 1 74 sum on or 10 PATENTED JAN 1 4 SHEET US UP 10 FIG /2 SHEET as or 10 PATENTEDJAN 1 1914 momm 0w OWN E y M A 0 5 ON PATENTED JAN 1 I974 SHEET 07 or 10 PATENTEDJAN 1 I914 sum '08 0F 10 PATENTED JAN 1 74 mm mar 10 SWITCHING SYSTEM FOR A TRANSPORTATION SYSTEM EMPLOYING A GUKDEWAY This invention relates to switching apparatus and, more particularly, to a switching system for a ground transportation system of the type employing a guideway and vehicles adapted to travel along the guideway.

Several ground transportation systems have been developed or proposed in which guideways, generally of approximately U-shaped cross-section, are provided for supporting and guiding various types of vehicles along predetermined routes. The guideway of such a system typically employs left and right, upright guide walls and a generally horizontal road surface, extending at least partially between the guide walls, for supporting the vehicles. Vehicles have been constructed which travel along such guideways upon resilient tires and which include following mechanisms adapted to engage the guide walls for guiding or steering the vehicles within the guideways. Alternatively, the following mechanisms may engage guide rail structures, in which case the guideway may consist only of a roadway and at least one guide rail structure extending along or alongside the roadway. Vehicles of the above type are similar to railway cars in many respects, but can provide advantages, such as improved riding qualities and quieter operation, over conventional railway vehicles. Guideway transportation systems are also suited for use with other types of vehicles, such as those employing ground-effect, air cushion, supporting means. Such ground-effect vehicles have great potential for highspeed ground transportation systems and, when adapted to travel within a guideway, can be safely and precisely maneuvered.

While the construction of guideway transportation systems is analogous to that of conventional railway systems in some respects, in other respects it differs radically therefrom, presenting a number of engineering problems to the designer. One such problem, to which the present invention is addressed, relates to the provision in such systems of practicable and reliable switching apparatus. The roadway, or the area normally extending between parallel guide walls, is required to be substantially clear of obstructions over at least largeportions of its width in order that it may serve as a continuous, smooth-surfaced ramp upon which the tires or other supporting means of the vehicles may ride. This requirement varies according to the design of the system, e.g., according to the particular guidance system employed by the vehicles and the configuration of the tires of other supporting means, but in general there are necessarily relatively wide areas of the roadway which must remain substantially unobstructed if the vehicles are to achieve safe, smooth'passage. This is in contrast to conventional railway systems, wherein the rails serve both to support and guide the cars, and wherein the area between the rails is not associated with the cars. Switching systems for conventional railways utilize the space between diverging, outer rails in switch junctions for the placement of dual, movable rails which divert the cars to one or the other of two, diverging, railway lines, it being required only that narrow gaps remain between the rails upon which the wheels ride and the other rails to permit passage of the flanges of the wheels. Because of the requirement, in guideway systems, that substantial portions of the roadway be clear of obstructions, such moveable switching rails cannot be conveniently adapted for use in switches for guideway systems. It can thus be seen that the development of efficient switching apparatus for use in guideway transportation systems requires the solution of engineering problems unique to such guideway systems.

Switching systems of several types have been proposed for guideway systems, but they suffer from a number of disadvantages. One approach has been to provide a relatively massive, movable, blade structure in a junction of two, mutually diverging, guideway portion, the blade structure extending longitudinally along the entire length of the junction and being pivotably mounted in such a manner that a distal end section thereof may be selectively positioned along side one or the other guide walls at the entrance to the junction, i.e., at the end of the junction at which the diverging guideway portions are merged. The blade structure then serves to divert approaching vehicles into a selected one of the mutually diverging guideway portions. The massive blade structures of such switches must be constructed and mounted with sufficient precision to ensure accurate alignment of the blade structure with adjacent portions of the guide walls in both positions of the blade structure, all of which tends to increase the cost of the system because of the difficulty of manufacturing and mounting large, precisely dimensioned structures. The size and weight of such a blade structure also necessitate the use of powerful and fairly complex actuating mechanisms for positioning the blade structure. Moreover, because the distal end of the blade structure sweeps across the entire width of the guideway junction during each change of position, any foreign objects which lie on the roadway in the path of the blade may become entrapped in the operating mechanism, or between the blade structure and an adjacent guide wall, and possibly cause a malfunction of the switch. It is, of course, highly desirably that switching apparatus be designed so that the possibility of serious malfunction, for any reason, is substantially eliminated.

Another type of switching mechanism which has been used in guideway systems employs guide rails extending alongside the guideway within the junctions for directioning the vehicles, guide rollers suitably being mounted on the vehicles for engaging respective ones of the guide rails. A plurality of such guide rails are moveably positioned along the sides of a switching junction in such a manner that mutually parallel rails respectively positioned on opposite sides of the junction can be moved simultaneously from one position to another, remaining in parallel alignment, for directioning passing vehicles along a desired route. In at least one such switching system, at least four, moveable, guide rail elements are repositioned during each switching cycle; moreover, certain pairs of mutually adjacent rails must be positioned in mutually abutting, longitudinal alignment while other pairs of the rails must be in parallel alignment. This requirement of precise positioning of a number of moveable rail elements is undesirable in that the operating mechanism of the switch'is required to be complex and precise, adding to the expense of manufacture and the likelihood of malfunction. I

It is, accordingly, a major object of the present-invention to provide a new and improved switching system for'use in guideway transportation systems.

Another object is to provide a guideway switching system which is of reliable and efficient operation.

Yet another object is to provide such a switching system which eliminates the need for precise alignment of a plurality of movable, guide rail elements.

Another major object is to provide such a switching system which can be actuated by conventional switch actuating mechanisms of proven reliability in general railway use.

A further object is to provide such a switching system in which the danger of jamming or binding of a movable guide rail by foreign objects alongside the movable guide rail is substantially eliminated.

Still another object is to provide a switching apparatus which provides the above-stated advantages but nevertheless is of simple construction, having only one major, movable part, and which is thus of relatively inexpensive, practicable manufacture.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawing illustrative of the invention.

In the drawing:

FIG. 1 is a diagrammatic representation of a guideway transportation system employing switching apparatus constructed according to the present invention;

FIG. 2 is a plan view of switching apparatus constructed according to a preferred embodiment of the present invention and showing a junction of mutually diverging guideway portions and portions of a vehicle within the junction, the movable rail structure of the switching system being shown in its first position;

FIG. 3 is a view similar to FIG. 2 showing the movable rail structure in its second position;

FIG. 4 is a plan view in an enlarged scale of portions of the switching apparatus of FIGS. 2 and 3, showing the movable rail structure in its second position and showing portions of the left and right, guide wheel assemblies of the vehicle;

FIG. 5 is a fragmentary, cross-sectional view taken along the line V-V of FIG. 4 and showing portions of the switching apparatus in an enlarged scale relative to FIG. 4;

FIG. 6 is a cross-sectional view, taken partially along the line VI-Vl of FIG. 4, of a portion of the switching apparatus of FIGS. 2-5 and showing the left, front, guide wheel assembly adjacent the movable rail structure;

FIG. 7 is a top view of a modification of the movable rail structure of FIGS. 2-6;

FIG. 8 is a top view of a modification of the guide wheel assembly;

FIG. 9 is a top view of a further modification of the guide wheel assembly;

FIG. 10 is a rear view of the guide wheel assembly of FIG. 9 taken along the line X-X of FIG. 9 and showing, in cross-section, a portion of the second, fixed rail structure;

FIG. 11 is a top view of still another modification of the guide wheel assembly;

FIG. 12 is a view, similar to FIG. 10 and taken along the line XIIXII of FIG. 11, showing the guide wheel assembly of FIG. 11 engaged by a portion of the second, fixed rail structure; and

FIG. 13 is a rear, perspective view of the guide wheel assembly of FIGS. 11 and 12 and showing a portion of the movable rail structure in its second position;

FIG. 14 is a plan view, similar to FIG. 2, showing a modification of the switching system of FIGS. 2-6;

FIG. 15 is a plan view, similar to FIG. 4, of the modification of FIG. 14; FIG. 16 is a cross-sectional view, taken as on the line XVIXVI of FIG. 15, of portions of the modified switching system of FIGS. 14 and 15;

FIG. 17 is a plan view, similar to FIGS. 2 and 14, of another modification of the switching system;

FIG. 18 is a fragmentary, cross-sectional view taken as on the line XVIIIXVIII of FIG. 17;

FIG. 19 is a diagrammatic view of a portion of the guideway system of FIG. 1 in an enlarged scale and showing schematically portions of a control system of a type suitable for use with switch systems constructed according to the present invention;

FIG. 20 is a view, partially cut away, and similar to FIG. 4, of a further modification of the switching system which is particularly adopted for receiving vehicles entering from its bifurcated, second end;

FIG. 21 is a fragmentary, cross-sectional view taken as on the Line XXI-XXI of FIG. 20; and

FIG. 22 is a fragmentary, cross-sectional view taken as on Line XXII-XXII of FIG. 20.

With initial reference to FIG. 1, a typical guideway transportation system employs at least one primary guideway 19, upon which through traffic may pass, and at least one secondary guideway 20 which branches off from the primary guideway by means of a switch 10 and which subsequently rejoins the primary guideway through a second switch l0(suitably of the passive type to be described in later section) which is reversed in direction. A plurality of the secondary guideways 20 is illustrated, each of which serves as a siding to permit loading and unloading of passengers and/or cargo without interrupting the continuous flow of traffic upon the primary guideway 19, the primary guideway being formed in a closed loop to permit continuous trafiic flow thereupon without reversing the direction of vehicles 12 (FIG. 1) to be described. Such a transportation system 9 is suited for use in applications wherein continuous operation is required for transporting a number of passengers to and from a plurality of destinations, as is required in congested areas such as airports, shopping centers, or cities or portions thereof. An exemplary means for controlling the switches 10 in such a guideway system will be discussed in a later section, but it should be noted that vehicles traveling along the main guideway 19 must pass through a great number of the switches 10 which connect with the secondary guideways 20. Thus, each switch system 10 must be reliably and continuously operative if the flow of traffic is to continue, and the malfunction of only one of the switches may cause the entire system 9 to be shut down. In automatically controlled guideway systems in which each vehicle may be independently routed to a respective one of a plurality of destinations, frequent operation of the switches 10 is required to accommodate the continuous flow of traffic, in contrast to a railway system in which there may be fewer destinations and in which the switches need not be individually positioned for each car, but rather are positioned once to accommodate a number of cars grouped into a train, or even a plurality of trains. Reliability of service over extended periods of time is thus of particular importance in such guideway switches 10.

With reference now to FIG. 2, a preferred embodiment of the switching system 10 is employed in a guideway transportation system of the type having a guideway, indicated generally at 11, and at least one vehicle 12 adapted to travel along and follow the guideway. The exemplary guideway 11 of the present embodiment is approximately U-shaped configuration, having a substantially horizontal, central roadway 113 for supporting the vehicle 1 2 and suitably having a pair of approximately upright curbs or parapets 14 extending alongside the roadway on opposite sides thereof. For clarity of description, the direction indicated by arrows (FIG. 2) and 15A (FIG. 3) or generally from left to right in FIGS. 2 and 3 of the drawing will be considered to be the normal or current direction of vehicular movement, it being understood that traffic in the reverse direction is also possible. The parapets 14 have respective sidewalls which face the roadway 13 and which, in compliance with the arbitrary directional sense denoted by arrows 15 and 15A, are termed left and right guide walls 16, .17. The guide walls 16, 17 of the present, illustrative guideway system are substantially perpendicular to the roadway l3 and are uniformly spaced from each other along the guideway 13. Alternatively, the guide walls 16, 17 may be sloped somewhat from the perpendicular, it being only necessary that they have some degree of vertical extension for providing lateral guidance.

The switching system 10 is suitable for use with various types of guideway following vehicles, and it is particularly adapted for use with vehicles of the type described in the co-pending application for U. S. Pat. entitled Guide Following Steering Apparatus filed on even date by W. P. Goode. The steering system of the above application is installed in a vehicle, herein illustrated diagrammatically as the vehicle 12 of FIGS. 2 and 3, which vehicle rides upon front and rear pairs 18, 19 of rubber-tired wheels, the wheels of each pair being interconnected by suitable steering linkages (not shown) preferably of the Ackerman type employed in automobiles. The front and rear steering linkages are, in turn, connected in such a manner that the wheels of the front pair 18 and of the rear pair 19 turn simultaneously and in opposite directions for causing the vehicle 12 to turn about a relatively short turning radius. The vehicle 12 is also equipped with means for movable engaging the guide walls 16, 17 and actuating the respective steering linkages for guiding the vehicle 12 along the guideway 11. Such means suitably includes front and rear, elongated, guideway-following structures 21, 22 which respectively extend horizontally, substantially across the guideway 11, and are posi tioned adjacent the front and rear pairs of wheels 18, 19, respectively. The elongated structures 21, 22 are longitudinally movable relative to their own length and laterally of the vehicle 12. Left and right, front guide wheel assemblies 24, 25, shown more clearly in FIG. 4, are fixedly joined to opposite ends of the front elongated structure 21, and left and right, rear guide wheel assemblies 26, 27 (FIG. 2) are similarly joined to the rear elongated structure 22. Each of the guide wheel assemblies 24, 25, 26, 27 includes a guide wheel (to be described below) rotatable about an approximately vertical axis and adapted to roll along a respective, adjacent guide wall, the guide wheel assemblies serving continuously to center the elongated structures 21, 22 between the guide walls l6, 17. Means are provided, as specifically disclosed in the aboveidentified application, for connecting one of the elongated structures 21,

22 to the interconnected, front and rear steering linkages for guiding the vehicle 12 along the guideway 11 between the guide walls 16, 17, the steering system of the Goode patent application employing for guidance only the respective on of the elongated structures 21, 22 which is positioned at the end of the vehicle 12 facing the current direction of travel. While directional terminology such as left, right, forward, and rearward are used herein for clarity-in describing the vehicle 12 and the switching system 10, in fact, the vehicle is substantially symmetrical and is operable in either direction with equal facility, as disclosed in the Goode patent application. While the switching system 10 is described herein with reference to its use with a vehicle as disclosed in the above-cited patent application, it is not, of course, limited to such use but is suited for guideway systems employing other types of vehicles having various types of suspension and steering systems. For example, the switching system 10 is equally applicable for guideway following vehicles in which the front and rear wheels are independently and simultaneously steered by respective, front and rear, guideway following mechanisms, and the switching system may also be used with vehicles employing ground-effect suspension means and designed to follow a guideway.

With respect now to the switching system 10 of the present invention and with continued reference to FIG. 2, a junction 32 has a first end 33 communicating with a first portion 34 of the guideway 11 and widened, bifurcated, second end 35 communicating with second and third, mutually diverging portions 36, 37 of the guideway, the second and third guideway portions 36, 37 being merged into the single, first guideway portion 34 at the first end 33 of the junction 32. The first and second guideway portions 34, 36 comprise, for example, portions of the primary guideway 19 of FIG. 1 while the third portion 37 comprises a portion of the secondary guideway 20.

If the direction indicated by the arrow 15 is taken as the current direction of traffic flow, the first end 33 of the junction 32 may be considered the inlet to the junction, and the second end 35 may be considered an exit end having first and second outlets 40, 41 communicating with the second and third guideway portions 36, 37, respectively. In actual operation, the switching system 10 is well suited for use in systems having bidirectional traffic flow, or it may be reversed in direction with respect to the current direction of traffic flow, as will be explained in a later section.

Parapet sections 42, each of cross-sectional configuration similar to that of the parapets 14 of the guideway 1 1, suitably extend along opposite sides of the junction 32 and have mutually facing side surfaces which define first and second, guide wall portions 43 and 44 of configurations corresponding to those of the left and right guide walls 16, 17, respectively. The first guide wall portion 43 extends along the left side of the junction 32 and is contiguous with the respective left guide walls 16 of the first and second guideway portions 34, 36; that is, the first guide wall portion 43 is contiguous at the second end 35 of the junction 32 with the guide wall of the second guideway portion 36 spaced farthest from the third guideway portion 37. The second guide wall portion 44 extends along the opposite side of the junction 32 and has a first end 45 contiguous, at the first end 33 of the junction 32, with the right guide wall 17 of the first guideway portion 34 and a second end 46,

at the second end 35 of the junction, contiguous with the guide wall of the third guideway portion 37 spaced farthest from the second guideway portion 36, i.e., contiguous with the right guide wall of the third guideway portion 37 as viewed in the drawing. The second guide wall portion 44 thus diverges continuously, in the direction from its first end 45 to its second end 46, from the first guide wall portion 43. The roadway 13 extends along the entire length of the junction 32 and at least partially across its width between the first and second guide wall portions 43, 44; the roadway 13 necessarily occupies the portions of the junction over which the wheels 18, 19 of the vehicle 12 must pass. Preferably, the roadway 13 extends continuously between the first and second guide walls portions and is continuous, or at least contiguous, with the portions of the roadway in the first, second, and third guideway portions 34, 36, 37.

With added reference to FIGS. 4 and 5, a first fixed rail structure 49 of L-shaped, cross-sectional configuration is rigidly affixed to the parapet section 42 defining the second guide wall portion 44. The first, fixed, rail structure 49, in cross section, has a horizontal leg or portion 50 which, for example, is seated upon the surface of the respective, adjacent, parapet section 42, is suitably bolted to the parapet section, and projects therefrom over the roadway 14. A substantially vertical rail portion projects downwardly from the distal portion of the horizontal rail portion 50 and constitutes a fixed, first guide rail 51 extending along the length of the rail structure 49.

As seen most clearly in FIG. 2 the first fixed rail structure 49 extends along the second guide wall portion 44 from the second end 35 of the junction 32 to a location on the second guide wall portion 44 spaced from the junction first end 35. The spacing of the first fixed rail structure 49 from the first end' 33 of the junction 32 is such that the portion of the first fixed rail structure 49 closest to the opposite, first guide wall portion 43 is spaced from the first guide wall portion 43 by a distance at least as great as the gauge of the guideway 11, i.e., the distance between the left and right guide walls l6, 17. With particular reference to FIGS. 4 and 5, the first guide rail 51 projects downwardly from the horizontal guide rail portion 50 toward the roadway 13 and extends alongside the second guide wall portion 44 at a constant height above the roadway 13. The side of the vertical, first guide rail 51 which faces the second guide wall portion 44 constitutes a guide surface 52 which is substantially perpendicular to the roadway l3 and is continuous along the length of the first guide rail 51, the guide surface 52 being spaced from the second guide wall portion 44 by a constant, predetermined distance.

A second fixed rail structure 55 (FIG. 2), of L- shaped cross-sectional configuration corresponding to that of the first rail structure 49, extends along the first guide wall portion 43 from the second end 35 of the junction 32 toward the junction first end 33 to a location along the first guide wall portion 43 spaced from the first end 33 of the junction by a distance greater than the distance between the first end of the junction and the first fixed rail structure 49. With added reference to FIGS. 4 and 5, the second fixed rail structure 55, in cross section, has a horizontal portion 56, rigidly affixed to the parapet section 42 which defines the first guide wall portion 43, and a vertical portion projecting downwardly toward the roadway l3 and constituting a fixed, second guide rail 57. The second guide rail 57 extends alongside the first guide wall portion 43 at a constant height above the roadway 13, and preferably at a higher equal to that of the first guide rail 51, for reasons which will become apparent. The surface of the second guide rail 57 which confronts the first guide wall portion 43 constitutes a guide surface 58 spaced from the first guide wall portion by a constant distance also preferably equal to the distance between the guide surface 52 of the first guide rail 41 and the second guide wall portion 44. The guide surface 58 of the second guide rail 47 is substantially perpendicular to the roadway 13 and is continuous along the length of the second rail structure 55.

Between the first end 33 of the junction 32 and the second fixed rail structure is positioned a single movable rail structure 61 (FIGS. 2-6), also of L- shaped, cross-sectional configuration and having a horizontal portion 62 and a vertical portion, constituting a movable, third guide rail 63, projecting downwardly from the horizontal portion 62 toward the roadway 13. The movable rail structure 61 is pivotably mounted upon a bearing 65 (FIG. 4) and rotatable about a rotational axis substantially perpendicular to the roadway 13. The bearing 65 is fixed relative to and preferably seated upon the parapet section 42 defining the first guide wall portion 43. The third guide rail 63 is thus pivotally supported over the roadway 13 adjacent the first guide wall portion 43. The third guide rail 63 has a first end 67 positioned adjacent the junction first end 33 and a second end 68 adjacent the second fixed rail structure 55, and pivot point represented by bearing 65 being spaced between the first and second ends of the third guide rail and spaced from the second end 68 (for example) approximately one-third the length of the movable, third guide rail 63. With particular reference to FIG. 5, the third guide rail 63 has first and second, oppositely-facing guide surfaces 71, 72 each substantially perpendicular to the surface of the roadway 13, the first guide surface 71 confronting the first guide wall portion 43 and second guide surface 72 facing toward the second guide wall portion 44.

In the present, illustrative example of the switching system 10, the second guide wall portion 44 and the second and third rails 57, 63 extend substantially linearly, the first and second guideway portions 34, 36 being longitudinally aligned and constituting a through" or main route corresponding to the primary guideway 19 of FIGS. 1 and 19; the first guide wall portion 43 and the adjacent, first guide rail 51 are curved to conform with the gradual divergence of the first guide wall portion 43 from the second guide wall portion 44. In other embodiments of the switch '10 in which, for example, the junction 32 is in a symmetrical, Y-shaped configuration (not shown), the second guide wall portion 43 and the second and third guide rails 57, 63 are also curved.

The movable rail structure 61 is pivotable between a first position (FIG. 2) in which the movable rail structure 61 is longitudinally aligned with the second fixed rail structure 55 and a second, divert" position (FIGS. 3-5). When the movable rail structure 61 is in its first position, (as shown in FIG. 2), the second end 68 (FIG. 4) of the third guide rail 63 is contiguous with the adjacent end of the second guide rail 57, and the first guide surface 71 of the third guide rail 63 is equidistant, along the length of the third guide rail, to the first guide wall portion 43; in the second position (FIGS. 35), the first end 67 of the third guide rail 63 is positioned immediately adjacent the first guide wall portion 43 and the second end 68 is spaced outwardly from the first guide wall portion 43 beyond the second fixed rail structure 55. The third guide rail 63 is of sufficient length, relative to the spacing between its first end 67 and the bearing 65, and is positioned in such a manner that, upon the third guide rail being in its second position (FIG. 4), the distance between the second guide surface 72 of the third guide rail 63 from the second guide wall portion 44, taken along a line perpendicular to the second guide surface 72 and intersecting the second end 68 of the third rail 63, is approximately equal to the gauge of the guideway 11, or the distance between the left and right guide walls 16, 17 across the roadway 11 outside the junction 32.

In a passive merge switch (FIGS. -22) to be described, no provision is made for automatically positioning the moveable rail structure 61. However, in the switch 10 of FIGS. 2-6 in which the moveable rail structure 61 is positioned for directing traffic toward a preselected one of the outlets 40, 41, an actuating mechanism 74 (FIG. 4) is provided for positioning the movable guide tail structure 61 in a selected one of its two positions, the actuating mechanism 74 suitably being of conventional design and of the type employed for actuating railway switches. One such switch actuating mechanism which can be effectively adapted for use with the present switch system 10 is manufactured by the General Railway Signal Company as Model 55-G. Inasmuch as the operation of such switch actuating mechanism is known in the art, a detailed description thereof is not deemed necessary. In summary, however, the illustrative actuating mechanism 74 is operable to rotate an axle 75 projecting upwardly from the actuating mechanism and affixed to a rotatable arm 76 extending horizontally from the axle. The distal end of the rotatable arm 76 is pivotally connected, by a suitable bearing 77, to a connecting arm 78 which is positioned above the rotatable arm 76 and which extends horizontally from the bearing 77 generally toward the first end 67 of the third guide rail 63. The end of the connecting arm 78 which is spaced from the bearing 77 is suitably provided with a horizontal clevis 79, open toward the third guide rail 63, for permitting it to be pivotally connected to a laterally extending portion 80 of the movable rail structure 61, the extending portion 80 suitably comprising an extending portion of the horizontal portion 62 of the movable rail structure 61 which extending portion 80 projects over the first guide wall portion 43 and toward the actuating mechanism 74. From the axle 75, the rotatable arm 76 extends in a direction approximately opposite to the currently employed direction of traffic flow indicated by arrow 15A, and is rotatable in a counterclockwise direction, viewed from above as in FIG. 4, to a position, indicated by the line 81, in which its distal end is moved toward the roadway 11. This movement of the rotatable arm 76 is transmitted by the connecting arm 78 to the first end 67 of the third guiderail 63 to position the movable rail structure 61 and the third guide rail 63 in their first position; opposite or clockwise rotation of the rotatable arm 76 from the position indicated by line 81 is effective to reposition the movable rail structure 61 and third guide rail 63 in the second position, in which the first end 67 of the third guide rail is closely adjacent the first guide portion 43. In an alternative construction (not shown), the actuating mechanism 74 is provided with additional linkages to the movable rail structure 61 for locking the rail structure 61 in a selected position, for sensing the actual position of the rail structure 61, and for providing an electrical signal indicative of the position. The use of such redundant linkages as a safety measure is well-known in connection with railway switching applications and need not be shown in the drawing.

The switching system 10 additionally includes means on the vehicle 12 (FIG. 2) for engaging respective ones of the guide surfaces 52, 58, 71, and 72 (FIG. 4) as the vehicle passes through the junction 32. With continued reference to FIGS. 4 and 5 and added reference to FIG.

.6, the left, front, guide wheel assembly 24 has an elongated frame element 82 joined at a central portion thereof to the left end of the elongated structure 21 and suitably extending horizontally, approximately perpendicularly of the elongated structure 21. The left, front, guide wheel 29 is affixed to and suitably positioned below the forward end of the frame element 82 upon suitable bearings seated coaxially within the guide wheel 29 and oriented such that the guide wheel 29 is freely rotatable about a rotational axis substantially perpendicular to the roadway 13. A left, front, guide roller 83 is similarly affixed to the frame element 82 and is positioned above the frame element 82 and to the rear of the guide wheel 29 upon an upright post 85 connected to the frame element 82. The frame element 82 and the guide wheel 29 are positioned below the lowermost portions of the movable guide rail 63 and the second fixed guide rail and are thus free of contact with the guide rails 63, 57 during passage of the vehicle 12 (FIG. 2) through the junction 32. The post 85 supporting the guide roller 83 extends upwardly sufficiently to position the guide roller 83 in horizontal register with the second and third guide rails 57, 63. As seen most clearly in FIG. 6, the guide roller 83 is preferably offset, in the direction toward the adjacent, first guide wall portion 43, from the guide wheel 29 but is of sufficiently small diameter, relative to the diameter of the guidewheel 29, that, upon the guide wheel 29 being in contact with the first guide wall portion 43 adjacent the movable rail structure 61 when the movable rail structure is in its first or through position, the guide roller 83 is in register with the first guide surface 71 and positioned between the first guide surface 71 and the first guide wall portion 43. Similarly, upon the guide wheel 29 being adjacent the second fixed rail structure 55 and in contact with the first guide wall portion 43, the guide roller 83 is positioned between the first guide wall portion and the guide surface 58 of the second guide rail 57 and in register with the guide surface 58 of the second guide rail 57. The guide roller 83 is oriented such that its outermost portion, i.e., its edge portion most remote from the vehicle 12 (FIG.2) and confronting the first guide wall portion 43, is spaced inwardly from the outermost edge of the guide wheel 29 sufficiently for the guide roller 83 to clear the forward end 67 of the third guide rail 63 upon the guide roller assembly 24 being adjacent the movable rail structure 61 when it is in its second position as shown in broken lines in FIG. 6; suitably, the horizontal spacing between the respective, outermost portions of the guide wheel 29 and the guide roller 83 is approximately equal to the thickness of the downwardly extending, third guide rail 63 so that, upon the vehicle 12 (FIG. 3) entering the junction 32 from the junction first end 33, the guide roller 83 does not impact jarringly upon the leading edge of the third guide rail 63. As shown in FIGS. 4 and 5, the right front, guide wheel assembly 25 corresponds to the left front guide wheel assembly 24 and includes a guide roller 84 and a guide wheel 30, the guide roller being positioned between the second guide wall portion 44 and the guide surface 52 of the first guide rail 51 upon the right, front, guide wheel 30 contacting the second guide wall portion 44 adjacent the first guide rail 51.

The left, rear, guide wheel assembly 26 (FIG. 2) is symmetrical with respect to the left, front, guide wheel assembly 24 but is suitably reversed from front to rear; in the vehicle 12 described in the above-identified patent application by W. P. Goode, the left, rear, guide wheel assembly 26 is adapted to follow the path of the left, front, guide wheel assembly 24 when the vehicle 12 is traveling in a forward direction and the left, front, guide wheel assembly 24 is adapted to follow the left, rear, guide wheel assembly 26 when the vehicle 12 travels in the opposite direction. In a system in which bidirectional traffic flow occurs and as illustrated in the present, preferred embodiment, the left guide wheel assemblies 24, 26 are also constructed symmetrically with respect to the right guide wheel asse'mblies 25, 27, respectively, so that the guide rollers of each guide wheel may engage respective ones of the guide surfaces 52, 58, 71, 72 during movement of the vehicle 12 in either direction along the guideway 11 as well as during operation of the vehicle when it is turned about to face in an opposite direction. Similarly, in such a bidirectional system, the first fixed rail structure 49, with its first guide rail 51, is positioned above the roadway 13 and spaced from the second guide wall portion 44 symmetrically with respect to the positioning of the second fixed rail structure 55 and the movable rail structure 61 relative to the first guide wall portion 43 and the roadway 13, to permit engagement of the respective guide surfaces by the respective, adjacent guide wheels when the vehicle 12 is turned about to face in an opposite direction.

lt'will be apparent to those in the art that the guide wheel assemblies 24, 25, 26, 27 and guide rails 51, 57, 63 can be inverted (not shown) such that the guide rails 51, 57, 63 project upwardly and the guide wheel assemblies project downwardly. However, the preferred embodiment of FIGS. 2-6 provides the advantage that the horizontal rail portions 50, 56, and 62 serve to cover and protect the guide surfaces and guide wheel assemblies. The horizontal portion 62 of the moveable rail structure is extended over the adjacent parapet 42, in both the first-and second positions of the rail structure 63, so that foreign objects are thereby prevented from becoming trapped between the moveable rail structure 63 and the first guide wall portion 43.

The operation of the switching system will now be described with respect to its use with the vehicle 12. In summary, and with reference to FIGS. 2 and 3, it will be seen that the single, movable rail structure 61 serves to guide a vehicle 12 entering the junction 32 from the first end 33 of the junction toward the first or the second outlet 40, 41, and that a respective one of the fixed rail structures 49, 55 then serves to continuously guide the vehicle along its-initial course and through the selected outlet. Assume first that it is desired to conduct vehicles traveling in the direction indicated by arrow 15 through the first outlet 40 and onto the second guide-way portion 36. If the movable rail structure 61 is in its second position as shown in FIG. 4, the actuating means 74 is energized by a control signal (according to methods known in the art) and caused to rotate the axle 75 and the rotatable arm 76 in a counterclockwise direction, as viewed from above, so that the connecting arm 78 is moved toward the guideway 11 and such that the leading end 67 of the third guide rail 63 is moved outwardly from the first guide wall portion 43 until the third guide rail 63 is longitudinally aligned with the second, fixed guide rail 57. The first guide surface 71 of the movable, third guide rail 63 is then equidistant along its length from the first guide wall portion 43. With the movable rail structure 61 thus in its first or through position as shown in FIG. 2, and upon a vehicle 12 entering the junction 32 from the junction first end 33, the left, front, guide wheel assembly 24 initially engages the movable rail structure 61. With reference to FIG. 6, the guide wheel 29 of the left, front, guide wheel assembly 24 is in contact with the first guide wall portion 43 as the vehicle 12 (FIG. 2) enters the junction, and the guide roller 83 of the guide wheel assembly 29 enters the space between the first guide surface 71 and the first guide wall portion 43 to become entrapped by the movable rail structure 61. As the vehicle 12 proceeds along the junction 32, the junction widens, and the second guide wall portion 44 diverges from the first guide wall portion 43 and no longer contacts the guide wheel 30 of the right guide wheel assembly 25. At this point, the left, front, guide wheel assembly 24 alone serves to guide the vehicle 12; the guide roller 83 is adapted to roll against the first guide surface 71, and serves to prevent the elongated follower structure 21 from drifting away from the first guide wall portion 43; and, the guide wheel 29 serves to limit movement of the elongated structure 21 in an opposite direction or toward the first guide wall portion 43. The front, left, guide wheel assembly 24 subsequently engages the second guide rail 57 (FIG. 4), of the second fixed rail structure 55 and continues to guide the vehicle 12 through the junction 32 alongside the first guide wall portion 43 until the vehicle leaves the junction through the first outlet 40, whereupon the guide wheels 29, 30 of the guide rollers 24, 25 engage the guide walls 16, 17 of the second guideway portion 36 to guide the vehicle 12 along the second guideway portion. In the vehicle 12, the right and left, rear guide assemblies 27, 26 are not active in steering the vehicle 12 when the vehicle is traveling in a forward direction, and they merely track or follow the respective right and left, front guide wheel assemblies 25, 24. Thus, the left, rear, guide wheel assembly 26 follows the path of the left, front, guide wheel assembly 24 and also becomes entrapped initially by the movable rail structure 61 and subsequently by the second fixed rail structure 55 as the vehicle passes through the junction 32.

Alternatively, if a vehicle employing independent front and rear steering is employed, i.e., a vehicle wherein the front wheels 18 are steered by the front guide wheel assemblies 24, 25 while the rear wheels 19 are steered independently of the front wheels 18 by the rear guide wheel assemblies 26, 27, then the left, rear, guide wheel assembly 26 also follows the front, left, guide wheel assembly 24, as the vehicle enters the junction 32 from the junction first end 33, and also becomes engaged initially with the movable rail structure 61 and subsequently, with the second fixed rail structure 55. The left, rear, guide wheel assembly 26 in such a vehicle serves to actively steer the rear wheels 19 of the vehicle as it passes through the junction 32.

Upon the vehicle 12 entering the first end 33 of the junction 32 when the movable rail structure 61 is in its second or divert position as shown in FIG. 4, the third guide rail 63, of the movable rail structure 61, has its leading portion 67 positioned closely adjacent the first guide wall portion 43 so that the guide roller 83 of the front, left, guide wheel assembly 24 contacts the outer, second guide surface 72 instead of the first guide surface 71, thus diverting the front, elongated follower structure 21 and the vehicle 12, steered by the follower structure 21, away from the first guide wall portion 43 and toward the second guide wall portion 44, or generally toward the second outlet 41. The guide wheel 29 of the left, front, guide wheel assembly 24 is positioned below the third guide rail 63 anddoes not contact the guide rail 63 during the passage of the vehicle adjacent the movable rail structure 61, but the guide wheel 30 of the right, front, guide wheel assembly 25 remains in contact with the second guide wall portion 44. Thus, the vehicle 12 is steered by the guide roller 83 of the left, front, guide wheel assembly 24 and by the guide wheel 30 of the right guide wheel assembly 25 as it rolls along the second guide wall portion 44 between the junction first end 33 and the first, fixed, rail structure 49.

It will be apparent to those skilled in the art that if the second guide surface 72 is of linear, flat configuration along the length of the movable rail structure 61 and the second guide wall portion 44 confronting the movable rail structure 61 is curved, there will be a slight deviation in spacing between the second guide surface 72 and the second guide wall portion 44 along the length of the movable rail structure 61, which deviation is greatest at the mid-portion of the movable rail structure 61. Because the divergence of the second guide wall portion 44 is preferably a gradual one, this difference in effective track gauge is normally compensated for by a slight degree of play between the guide wheel assemblies 24, 25 and the second guide wall portion 44 and the second guide surface 72 and by the resilience of the guide wheels 29, 30. Alternatively, however, the length of the second guide wall portion 44 which confronts the movable rail structure 61 is of substantially flat configuration (not shown) between the first end 33 of the junction 32 and the first, fixed, rail structure 49, in which case the distance between the second guide wall portion 44 and the second guide surface 72 remains constant. In a further modification, shown in FIG. 7, the movable rail structure, 61A, is constructed with the vertical, third guide rail 63A contoured such that the external, second guide surface 72A curves inwardly as it approaches the center of the guide rail structure 61A and outwardly in the direction along the guide rail 63A toward the two end portions 67A, 68A of the guide rail 63A. The external, second guide surface 72A is curved to correspond with the curvature of the opposite, second guide wall portion 44 (FIG. 4) confronting the movable rail structure 61A, and, is positioned such that the spacing between the second guide surface 72A and the second guide wall portion 44 is uniform when the movable rail structure 61A is in its second position. The guide rail 63A is then positioned immediately above the adjacent parapet 42 (not shown) in order that its first end 67A can be pivoted over the parapet to bring the second guide surface 72A into approximate alignment with the first guide wall portion 43, when the guide wall 63A is in its second position, for engaging the guide roller 83.

With respect to the embodiment of FIGS. 4 and 5, because the spacing between the third guide rail 63 and the second guide wall portion 44 from the second end 68 of the third guide rail 63, when the movable rail structure 61 is in its second position, is approximately equal to the spacing between the left and right guide walls 16, 17 of the guideway 11, when the movable rail structure 61 is in its second position, the right, front, guide wheel assembly 25 rides against the second guide wall portion 44 as the right guide wheel assembly 25 approaches the first fixed rail structure 49. As shown most clearly in FIG. 5, the right, front, guide wheel 30 is then positioned below the lowermost portion of the first fixed guide rail 51 and is free of contact with the guide rail 51, but it preferably does contact and roll along the second guide wall portion 44. The guide roller 84 of the right, front, guide wheel assembly 25 is in register with the guide surface 52 of the fixed, first guide rail 51, enters the space between the guide surface 52 of the first guide rail and the second guide wall portion 44, and thereby becomes captured by the first fixed rail structure 49. As shown in FIG. 3, the vehicle 12 then continues through the junction 32 alongside the second guide wall portion 44, the right, rear guide wheel assembly 27 following the right, front, guide wheel assembly 25 and also becoming captured by the first fixed rail structure 49. The rail structure 49 thus restrains the vehicle 12 alongside the second guide wall portion 44 until the vehicle 12 passes through the second outlet 41 and onto the third guideway portion 37. It is thus apparent that the vehicle 12 can be steered by only one fixed guide rail of L-shaped configuration in cooperation with the adjacent guide wall portion, and such an arrangement is suitably employed beyond the junction 32 in an alternative embodiment (not shown) wherein only one guide wall is employed along the roadway. It will be apparent that the switch 10 is also adapted to pass vehicles which are traveling in an opposite direction, or which enter the junction from one of the exits 40, 41. The movable rail structure 61 is positioned in its first position for receiving vehicles entering from the first outlet 40 and in its second position for receiving vehicles entering from the second outlet 41.

From the above description, it can be seen that the switching system 10 comprises a relatively simple yet effective switching apparatus for guideway transportation systems. The first guide surface 71 of the movable, third guide rail 63, in cooperation with the left, front, guide wheel assembly 24, comprises a first guiding means for guiding the vehicle 12 alongside the first guide wall portion 43 (or for constraining the vehicle to travel alongside the first guide wall portion) and toward the second guideway portion 36 upon the vehicle 12 entering the junction 32 from the junction first end 33 when the third guide rail 63 is in its first position; and the second guide surface 72 on the third guide rail, in cooperation with the left, front, guide wheel assembly 24, comprises a second guiding means for diverting the vehicle from the first guide wall portion 43 and guiding it toward the second guide wall portion 44 (and toward the third guideway portion 37) upon the vehicle 12 entering the junction 32 through the first end 33 thereof when the third guide rail 63 is in its second position as shown in FIG. 2. Similarly, the guide surface 58 of the fixed, second guide rail 57, in cooperation with the left, front, guide wheel assembly 24, comprises a third guiding means for constraining and guiding the vehicle 12 through the junction 32 alongside the first guide wall portion 43 and through the first outlet 40 upon the vehicle 12 being initially constrained or guided alongside the first guide wall portion 43 by the first guide surface 71 of the movable, third guiderail 63. The guide surface 52 of the fixed, first guide rail, in cooperation with the right, front, guide wheel assembly 25, comprises a fourth guiding means, for guiding the vehicle 12 through the junction 32 alongside the second guide wall portion 44 (constraining the vehicle to travel alongside the second guide wall portion) and through the second outlet 41 upon the vehicle 12 being initially diverted toward the second guide wall portion by the second guide surface 72 of the movable guiderail 63, or by the second guiding means. The third and fourth guiding means each may also be considered to comprise a respective following means or guide wheel assembly 24, 25 mounted on the vehicle 12 and a respective elongated surface (guide surfaces 58 and 52, respectively) distinct from the adjacent guide wall portions 43, 44, having vertical extension, and fixedly located relative to the guide wall portions 43, 44. The guide roller 83 of the left, front, guide wheel assembly 24 also constitutes a first guide rail following means for movably engaging the first guide surface 71 of the third guide rail 63 and subsequently, the guide surface 58 of the second guide rail 57, upon the vehicle 12 passing through the junction 32 from the junction first end 33 when the third guide rail is in its first position and, upon the third guide rail 63 alternatively being in its second position, for movably engaging the second guide surface 72 of the third guide rail. The guide roller 84 of the right, front, guide wheel assembly 25 also constitutes a second following means mounted on the vehicle 12 for movably engaging the fourth guiding means, i.e., the guide surface 52 of the first fixed guide rail 51, upon the vehicle 12 being initially diverted toward the second guide wall portion 44 by the second guide surface 72 of the movable guide rail 63.

While the guide wheel assemblies 24, 25, 26, 27 of FIGS. 2-6 constitute examples of .a preferred embodiment, other, modified constructions are possible. For example, it may be desirable, for safety, to employ redundant guide wheels and guide rollers, as shown in FIG. 8. In this modification, the frame 82A is enlarged and extended so that it can also support a second, redundant guide wheel 29A and a redundant guide roller 83A positioned to the rear and in register with the guide wheel 29 and the guide roller 83, respectively. The redundant guide wheel 29A and guide roller 83A are each of slightly lesser diameter than the corresponding, primary guide wheel 29 and guide roller 83, respectively, so that only the primary guide wheel 29 and guide roller 83 are normally used. Should the guide roller 83, for example, fail during operation of the vehicle 12, the redundant guide roller 29A then serves to engage the respective, adjacent guide surface 58 for ensuring safe, continuous operation. Further, while the switching system 10 is well suited for use in guideway transportation systems which carry both passengers and cargo, it is also adapted for use in less sophisticated guideway systems such as those intended for transporting cargo exclusively. In such systems, noise and vibration during operation of the system may not be as ob- 5 jectionable as they are during the transporting of passengers, and simpler, less expensive contruction may be applicable. For example, while the use of freely rotatable guide rollers (83, 84) mounted for engaging respective ones of the guide surfaces of the several guide rails 51, 57, and 63 is preferred, rotatable guide rollers may not be required in less sophisticated systems. In an alternative configuration, as illustrated in FIGS. 9 and 10, the guide roller 83 (FIGS. 4-6) of the left, front, guide wheel assembly 24 (as well as the guide rollers of the other guide wheel assemblies) is replaced by an upright, fixed, elongated member 87 adapted to slideably engage the guide surface 58 or, alternatively, the guide surfaces 71 or 72 of the movable guide rail 63 (FIG. 6). The upright member 87 thus serves the same purpose as the guide roller 83 of FIGS. 4 and 5. The upright member 87 is preferably finished with a polished surface for minimizing friction between the member 87 and the guide surfaces 71, 72, and the guide surfaces are coated with a friction-reducing agent such as grease or graphite. A further modification of the guide wheel assembly 24 is shown (as 24C) in FIGS. 1 1-l3. A single guide wheel 29C is employed both as guide roller for engaging respective ones of the guide surfaces and as a guide wheel for guiding the vehicle 12 along the guideway 11. The single guide wheel 29C is constructed and positioned similarly to the left, front, guide roller 83 of the preferred embodiment of FIG. 6, but extends outwardly, toward the guide wall 43 and beyond the frame 82C, so that it is free to roll along the guide wall 43 and thus guide the vehicle 12 as do the guide wheels of the guide wheel structures of the preferred embodiment. As seen in FIG. 12, the guide roller 29C rolls along the first guide wall portion 43 and alongside the second guide rail 57, of the second fixed rail structure 55. In FIG. 13, the embodiment of FIGS. 11 and 12 is positioned as the single guide wheel 29C rolls against the second guide surface 72 of the movable rail structure 61 when the rail structure 61 is in its second or divert position. An advantage of the preferred embodiment of FIGS. 2-6 when compared with the embodiment of FIGS. 11-13 is that the guide rollers and guide wheels turn in a single rotational direction in all instances. In the modification illustrated in FIGS. 10-13, however, the single guide wheel 29C may be causd to roll alternately against the first guide wall portion 43 and, for example, the guide surface 58 of the second guide rail 57 (FIG. 12), causing its direction of rotation to reverse sharply and thus causing greater wear of the roller 29C than occurs with the embodiment of FIGS. 2-6. This can be minimized by biasing the steering of the vehicle 12 such that the vehicle tends to bear to the left or right, according to principles well-known in the art.

While the switching system 10 has been described thus far with reference to its use with a U-shaped guideway 11, it is not limited to such an application. Other guideway systems exist in which the vehicles are not guided by upright guide walls but rather are adopted to follow other guiding means, such as guide rail extending parallel to the roadway. For example, and with reference to FIG. 14, a modified switching system 10C is installed in a guideway system which employs a guideway 11C having a central guide rail 81, for guiding a vehicle 12C, rather than left and right guide walls 16, 17 (FIG. 2), the alternative guideway 11C consisting only of a horizontal roadway 13C and the central guide rail 81 projecting upwardly therefrom and extending parallel to the direction of travel. A vehicle 12C similar to the vehicle 12 of FIGS. 2 and 3 also has front and rear, elongated follower structures 21C, 22C. The vehicle 12C also has horizontally mounted guide wheels for following appropriate guide surfaces, but the guide wheels, such as the front, left and right guide wheels 29C, 30C, are adapted to engage and roll upon respective, opposite side surfaces of the center guide rail 81 for guiding the vehicle 12C. The typical, front guide wheels 29C, 30C are mounted horizontally beneath the front elongated structure 21A, for example, adjacent and to either side of the center thereof.

With reference to FIG. 16, the representative, front follower structure 21C also has left and right guide rollers 83C, 84C respectively mounted on the left and right end portions of the follower structure 21C and each projecting upwardly therefrom, the left and right guide rollers being of substantially the same configuration as the guide rollers illustrated by the single guide roller 29C of FIGS. 11-13.

A junction 32C, of first, second, and third portions 34C, 36C, 37C of the guideway 11C, is of a configuration, in plan, similar to the junction 32 (FIGS. 2 and 3) of the initially described guideway system employing a U-shaped guideway. The junction 32C is provided with first and second, fixed rail structures 49C, 55C and with a moveable rail structure 61C. The fixed rail structures 49C, 55C are positioned as are the first and second, fixed rail structures 49, 55 of the embodiment of FIGS. 2-6 but are suitably supported by a plurality of upright posts 90 mutually spaced along both sides of the junction 32C. The moveable rail structure 61C is supported by the single bearing 65 which is seated upon a suitable foundation 9. Actuating means 74 are also provided for positioning the moveable rail structure 61C as in the previous embodiment. With reference to FIG. 16, the fixed rail structures 49C and 55C are of U-shaped configuration, each having two, mutually spaced, downwardly projecting legs 92. The fixed rail structures 49C, 55C are adapted to engage respective ones of the guide rollers 83C, 84C when the rollers become positioned between the legs 92 of a respective one of the fixed rail structures, the guide rollers 83C, 84C being positioned in horizontal register with the legs 92 and being of smaller diameter than the spacing between the legs of the respective rail structures. The respective inner legs 92 of each fixed rail structure 49C, 55C (which are closest to the center of the junction 32C) have guide surfaces 52C and 58C which correspond to the guide surfaces 52, 58 of FIGS. 2-6. The opposite, outer leg 92 of the first fixed rail structure 49C defines a guide surface 59 which confronts the guide surface 52C, and the outer leg 92 of the second fixed rail structure 55C defines a guide surface 60 which confronts the guide surface 58C.

With added reference to FIG. 15, the moveable rail structure 61C is also of U-shaped, cross-sectional configuration over most of its length and has a downwardly projecting, third guide rail 63C having first and second guide surfaces 71C and 72C corresponding to the first and second guide surfaces 71 and 72 of the moveable, third guide rail 63 of the initially described embodiment. The first guide surface 71C is flat, along the length of the moveable rail structure 61C, while the second guide surface 72C is curved and diverges from the first guide surface 71C toward the two ends of the guide rail 63C as in the embodiment illustrated in FIG. 7. The moveable rail structure 61C also has an outer leg 94 spaced from the third rail structure 63C and defining a third guide surface which confronts and extends parallel to the first guide surface 71C.

The operation of the modified switching system 10C of FIGS. l4-16 is essentially the same as that of the previous embodiment but differs therefrom in that (l) the vehicle 12C is guided by the centered guide rail 81 as it enters the junction 32C, and (2) the U-shaped rail structures 49C, 55C, and 61C are operative to engage respective ones of the guide rollers (83C, 84C) without added cooperation from adjacent guide wall portions such as the first and second guide wall portions 43, 44 of FIGS. 2 and 3. As shown in FIG. 15, the front, elongated follower structure 21C is centered within the guideway 11C by engagement of the guide wheels 29C, 30C with the central guide rail 81 as the vehicle 12C approaches the junction 32C while in the first guideway portion 34C. The left, front, guide roller 83C is then in register with the moveable rail structure 61C upon the vehicle 12C entering the junction 32 from the first guideway portion 34C, and the guide roller 83C becomes engaged by a respective one of the guide surfaces 71C, 72C as in the initially described embodiment. With continued reference to FIG. 15, the left, front, guide roller 83C (shown in broken lines as it initially engages the moveable rail structure 61C) engages the second, outer guide surface 72C upon the moveable rail structure 61C being in its second position, and the second guide surface 72C gradually diverts the follower structure 21C and the vehicle 12C (FIG. 14) toward the opposite side of the junction 32C or generally toward the third guideway portion 37C (FIG. 14). The gentle curvature of the outer surface 72C (and of the surface 72A of FIG. 7) serves to minimize the jerk- (more precisely, the rate of lateral acceleration of the vehicle) toward the opposite side of the junction 32C and, because of the inertia of the vehicle 12C which acts against the diverting force exerted by the second guide surface 72C, the vehicle continues to roll alongside the moveable rail structure 611C with its front, left, guide roller 83C in contact with the second guide surface 72C until the follower structure 21C passes the moveable rail structure 61C. Alternatively, the second guide surface 72C may be of a continuously increasing curvature, from its leading end to its second end (not shown). As shown in solid lines in FIGS. 15 and 16, the right, front, guide roller 83C becomes engaged between the downwardly extending legs 92 of the first fixed rail structure 49C before the follower structure 21C looses guiding contact with the second guide surface 72C of the moveable rail structure 61C, and the first fixed rail structure 49C then serves to guide the vehicle 12C through the junction 32C and onto the third guideway portion 37C. Alternatively, if the moveable rail structure 61C is in the first position, in which it is longitudinally aligned with the second fixed rail structure 55C, the left, front, guide wheel 83C becomes engaged between the first and third guide surfaces 71C and 95 of the moveable rail structure 61C and the vehicle 12C is guided along the left side of the junction 23C by the movable rail structure, and subsequently by the 

1. In a transportation system of the type employing vehicles adapted to travel along a guideway comprising a roadway and structure providing at least one guide surface, having vertical extension, extending along the guideway for guiding the vehicle, the system including a plurality of guideway junctions, each junction having a first end communicating with a first portion of the guideway and a widened, bifurcated, second end communicating with second and third, mutually diverging portions of the guideway, the transportation system including at least one primary guideway and at least one secondary guideway, having inlet and outlet ends, connected to the primary guideway by respective, oppositely directioned switching systems, the transportation system further including programmable control means for sensing the positions of the respective vehicles and for automatically actuating respective ones of the switching systems at appropriate times in response to the movement of the respective vehicles and according to respective, preselected routes programmed in the control system with respect to each vehicle, an improved switching system adapted for use in such a transportation system, the switching system comprising: a single movable guide rail positioned adjacent the first end of the junction and pivotable about an approximately vertical axis between first and second positions; first guiding means, comprising a first guide surface on the movable guide rail, for guiding a vehicle toward the second guideway portion upon the vehicle entering the junction from the junction first end when the movable guide rail is in its first position; and second guiding means, comprising a second guide surface on the movable guide rail, for guiding a vehicle toward the third guideway portion upon the vehicle entering the junction from the junction first end when the movable guide rail is in its second position, third guiding means, immovably positioned between the movable guide rail and the second guideway portion, for guiding a vehicle through the junction and onto the second guideway portion upon the vehicle being initially guided by the first guiding means; and fourth guiding means, immovably positioned between the first end of the junction and the third guideway portion, for guiding a vehicle through the junction and onto the third guideway portion upon the vEhicle being initially guided by the second guiding means.
 2. The switching system of claim 1, wherein the fourth guiding means comprises a means for guiding a vehicle toward the first guideway portion upon the vehicle entering the junction from the third guideway portion, wherein the third guiding means comprises a means for guiding a vehicle toward the first guideway portion upon the vehicle entering the junction from the second guideway portion, wherein the second guiding means comprises a means for guiding a vehicle through the junction and onto the first guideway portion upon the vehicle being initially guided by the fourth guiding means, and wherein the first guiding means comprises a means for guiding a vehicle through the junction and onto the first guideway portion upon the vehicle being initially guided by the third guiding means.
 3. In a transportation system employing at least one vehicle adapted to travel along a guideway having two mutually spaced guide walls having vertical extension, the system including a first guideway portion and second and third, mutually diverging guideway portions each having a pair of mutually spaced guidewalls having vertical extension, a switching system comprising: a junction of the first, second, and third portions of the guideway, the junction having a first end which communicates with the first guideway portion and a widened, second end having a first outlet communicating with the second guideway portion and a second outlet communicating with the third guideway portion, the junction having a first guide wall portion contiguous, at the first end of the junction, with one of the guide walls of the first guideway portion and contiguous, at the second end of the junction, with the guide wall of the second guideway portion spaced farthest from the third guideway portion, and a second guide wall portion extending between the other guide wall of the first guideway portion and the guide wall of the third guideway portion spaced farthest from the second guideway portion, the second guide wall portion diverging from the first guide wall portion in the direction, along the second guide wall, from the junction first end to the second outlet; a single moveable guide rail positioned adjacent the first guide wall portion and extending from the first end of the junction to a location between the junction first and second ends, the moveable guide rail being pivotable about a substantially vertical axis between a first position, in which the moveable guide rail is equidistant, along its length, from the first guide wall portion, and a second position in which the moveable guide rail diverges from the first guide wall portion and toward the second guide wall portion in the direction, along the moveable guide rail, from the first end and toward the second end of the junction; first guiding means, on the moveable guide rail, for constraining the vehicle to travel alongside the first guide wall portion upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its first position; second guiding means, on the moveable guide rail, for diverting the vehicle from the first guide wall portion and toward the second guide wall portion upon the vehicle entering the junction through the junction first end when the moveable guide rail is in its second position; third guiding means for constraining the vehicle to travel through the junction alongside the first guide wall portion and through the first outlet upon the vehicle being initially constrained to travel alongside the first guide wall portion by the first guiding means; and fourth guiding means for constraining the vehicle to travel through the junction alongside the second guide wall portion and through the second outlet upon the vehicle being initially diverted toward the second guide wall portion by the second guiding means.
 4. The switching system of claim 3, the third and fourth guiding means each comprising a respective folloWing means mounted on the vehicle and a respective, elongated surface distinct from the guide wall portions, having vertical extension, and fixedly located relative to a respective one of the first and second guide wall portions of the junction.
 5. The switching means of claim 4, the following means of the third guiding means being operative for engaging the elongated surface of the third guiding means upon the vehicle having entered the junction first end when the movable guide rail is in its first position, and the following means of the fourth guiding means being operative for engaging the elongated surface of the fourth guiding means upon the vehicle having entered the junction first end when the moveable guide rail is in its second position.
 6. The switching system of claim 3, further comprising positioning means for moving the moveable guide rail from its second to its first position.
 7. The switching system of claim 3, the positioning means comprising means resiliently urging the moveable guide rail to its first position.
 8. The switching system of claim 3, the positioning means comprising an actuator operable for selectively moving the moveable guide rail between its first and second positions.
 9. The system of claim 3, the guideway having an approximately horizontal roadway extending at least partially between the first and second guide wall portions of the junction and the moveable guide rail being positioned over the roadway and between the first and second guide wall portions.
 10. The system of claim 3, wherein the first guiding means comprises a guide surface extending along the length of the moveable guide rail, facing the first guide wall portion, and equidistantly spaced along its length from the first guide wall portion when the moveable guide rail is in its first position, and wherein the second guiding means comprises a guide surface extending along the length of the moveable rail and facing toward the second guide wall portion.
 11. The system of claim 3, wherein there is provided a first, fixed guide rail immoveably supported adjacent the second guide wall portion, the fourth guiding means comprising a guide surface extending along the first fixed guide rail and confronting the second guide wall portion, and wherein there is further provided a second fixed guide rail immoveably supported adjacent the first guide wall portion, the third guiding means comprising a guide surface extending along the second fixed guide rail and confronting the first guide wall portion.
 12. In a transportation system employing at least one vehicle adapted to travel along a guideway, the guideway comprising a roadway bordered by left and right, mutually parallel, approximately upright guide walls, each vehicle having apparatus including left and right guide wall following structures adapted to ride against the left and right guide walls, respectively, for guiding the vehicle along the roadway between the guide walls, a switching system comprising: a junction of a first portion of the guideway and of second and third, mutually diverging portions of the guideway, the junction having a first end communicating with the first guideway portion and at which the mutually diverging, second and third guideway portions are merged, and a bifurcated, widened, second end communicating with the second and third guideway portions, the junction having a first guide wall portion extending between respective ones of the guide walls of the first and second guideway portions and a second guide wall portion having a first end contiguous with the other guidewall of the first guideway portion and a second end located adjacent the second end of the junction and contiguous with the guide wall of the third guideway portion spaced farthest from the second guideway portion, the second guide wall portion diverging, from its first to its second end, from the first guide wall portion; a first guide rail immoveably positioned over the roadway adjacent the second guide wall pOrtion and extending alongside the second guide wall portion at a constant height above the roadway, the first guide rail having a guide surface substantially perpendicular to the roadway, continuous along the length of the first guide rail, facing the second guide wall portion, and spaced from the second guide wall portion by a constant, predetermined distance, the first guide rail extending from the second end toward the first end of the second guide wall portion, the first guide rail being spaced from the junction first end and spaced from the first guide wall portion by a distance at least as great as the spacing between the left and right guide walls of the guideway; a second guide rail immovably positioned over the roadway adjacent the first guide wall portion and extending alongside the first guide wall portion at a constant height above the roadway, the second guide rail having a guide surface substantially perpendicular to the roadway, continuous along the length of the second guide rail, facing the first guidewall portion, and spaced from the first guidewall portion by a constant, predetermined distance, the second guide rail extending from the bifurcated, second end of the junction toward the junction first end and being spaced from the junction first end by a distance greater than the distance between the junction first end and the first guide rail; a third guide rail constituting a single, movable guide rail, having first and second ends and pivotally supported over the roadway adjacent the first guide wall portion and between the second guide rail and the first end of the junction, the third guide rail having first and second, oppositely facing guide surfaces each substantially perpendicular to the roadway, the first guide surface of the third guide rail facing the first guidewall portion, the third guide rail being pivotable, about a rotational axis substantially perpendicular to the roadway and spaced between the first and second ends of the third guide rail, between a first position in which the second end of the third guide rail is contiguous with the second guide rail and in which the first guide surface of the third guide rail is equidistant, along its length, from the first guidewall portion, and a second position in which the first end of the third guide rail is positioned immediately adjacent the first guide wall portion and in which the third guide rail second end is spaced, from the first guide wall portion, beyond the second guide rail and in which the distance between the second guide wall portion and the second guide surface of the third guide rail, along a line perpendicular to the second guide wall portion and intersecting the second end of the third guide rail, is substantially equal to the distance between the left and right guide walls of the guideway; first guide rail following means, mounted on the at least one vehicle, for movably engaging the first guide surface of the third guide rail, and subsequently, the guide surface of the second guide rail, upon the vehicle passing through the junction from the junction first end when the third guide rail is in its first position and, upon the third guide rail alternatively being in its second position, for movably engaging the second guide surface of the third guide rail and diverting the vehicle toward the second guide wall portion; and second guide rail following means, mounted on the vehicle, for movably engaging the guide surface of the first guide rail and guiding the vehicle along the second guidewall portion and into the second portion of the guideway upon the vehicle being diverted toward the second guide wall portion by the first guide rail following means.
 13. The switching system of claim 12, wherein the first guide rail following means comprises a first guide roller rotatable about an axis perpendicular to the roadway and having a diameter less than the spacing between the first guide wall portion and the guide surface of the second guide rail and less than the spacing Between the first guide wall portion and the first guide surface of the third guide rail upon the third guide rail being in its first position, and wherein the second guide rail following means comprises a second guide roller rotatable about an axis perpendicular to the roadway and having a diameter less than the spacing between the first guide rail and the second guide wall portion, the second guide roller being positioned between the first guide rail and the second guideway portion upon the first guide roller being adjacent the second end of the third guide rail and in contact with the second guide surface of the third guide rail when the third guide rail is in its second position.
 14. The switching system of claim 12, further comprising a first guide wheel mounted on the vehicle adjacent the first guide roller, the first guide wheel being spaced vertically from the third guide rail upon the first guide roller being in contact with the third guide rail and spaced vertically from the second guide rail upon the first guide roller being in contact with the second guide rail, and a second guide wheel mounted on the vehicle adjacent the second guide roller, the second guide wheel being spaced vertically from the first guide rail upon the second guide roller wheel being in contact with the first guide rail.
 15. The switching system of claim 14, wherein the first guide wheel is adapted to contact and roll along the first guide wall portion upon the vehicle being adjacent the first guide wall portion, the first guide roller being spaced from the first guide wall portion, upon the first guide wheel contacting the first guide wall portion, by a distance approximately equal to the thickness, between the first and second guide surfaces, of the third guide rail.
 16. The switching system of claim 14, wherein the first and second guide wheels respectively confront and are each adapted to roll along a respective one of the guide walls, external of the junction, and each constituting a respective portion of a respective one of the left and right guide wall following structures.
 17. The switching system of claim 12, wherein the first and second guide rails constitute portions of first and second, fixed, L-shaped rail structures, respectively, and the third guide rail constitutes a portion of a moveable, L-shaped rail structure, each rail structure having, in cross-section, a horizontal portion extending between the respective guide rail and the respective, adjacent, guide wall portion.
 18. The switching system of claim 17, wherein the first and second guide wall portions respectively constitute mutually confronting sidewalls of first and second upright curbs extending along respective sides of the junction, and wherein the horizontal portions of the first and second L-shaped rail structures extend over and are rigidly affixed to the second and first curbs, respectively, and wherein the horizontal portion of the third L-shaped rail structure extends over and is pivotally mounted on the first curb.
 19. The switching system of claim 17, wherein the first, second, and third guide rails project downwardly from the horizontal portions of the respective L-shaped rail structures.
 20. In a transportation system employing at least one vehicle adapted to travel along a guideway comprising a roadway and structure providing at least one guide surface, having vertical extension, extending along the guideway for guiding the vehicle, the system having a junction having a first end communicating with a first portion of the guideway and a widened, bifurcated, second end communicating with second and third, mutually diverging portions of the guideway, a switching system comprising: a single moveable guide rail positioned adjacent the first end of the junction and pivotable about an approximately vertical axis between first and second positions; first guiding means, comprising a first guide surface on the moveable guide rail, for guiding a vehicle toward the second guideway poRtion upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its first position; and second guiding means, comprising a second guide surface on the moveable guide rail, for guiding a vehicle toward the third guideway portion upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its second position, third guiding means, immoveably positioned between the moveable guide rail and the second guideway portion, for guiding a vehicle through the junction and onto the second guideway portion upon the vehicle being initially guided by the first guiding means; and fourth guiding means, immoveably positioned between the first end of the junction and the third guideway portion, for guiding a vehicle through the junction and onto the third guideway portion upon the vehicle being initially guided by the second guiding means.
 21. The switching system of claim 20, wherein the first and second guide surfaces constitute guide surfaces extending along opposite sides of the moveable guide rail.
 22. The switching system of claim 21, including following means mounted on the vehicle and operative for engaging the first guide surface of the moveable guide rail upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its first position and for engaging the second guide surface of the moveable guide rail upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its second position.
 23. The switching system of claim 20, wherein the fourth guiding means also comprises a means for guiding a vehicle toward the first guideway portion upon the vehicle entering the junction from the third guideway portion, wherein the third guiding means comprises a means for guiding a vehicle toward the first guideway portion upon the vehicle entering the junction from the second guideway portion, wherein the second guiding means comprises a means for guiding a vehicle through the junction and onto the first guideway portion upon the vehicle being initially guided by the fourth guiding means, and wherein the first guiding means comprises a means for guiding a vehicle through the junction and onto the first guideway portion upon the vehicle being initially guided by the third guiding means.
 24. The switching system of claim 23 and further comprising positioning means for moving the moveable guide rail from its second to its first position.
 25. The switching system of claim 24, the positioning means comprising means resiliently urging the moveable guide rail to its first position.
 26. The switching system of claim 24, the positioning means comprising an actuator operable for selectively moving the moveable guide rail between its first and second positions.
 27. In a transportation system employing at least one vehicle adapted to travel along a guideway having an approximately horizontal roadway extending between left and right, approximately upright guidewalls, the system including a first guideway portion and second and third, mutually diverging guideway portions, a switching system comprising: a junction of the first, second, and third portions of the guideway, the junction having a first end which communicates with the first guideway portion and at which the second and third guideway portions are merged and a widened, bifurcated, second end having a first outlet communicating with the second guideway portion and a second outlet communicating with the third guideway portion, the junction having a first guide wall contiguous, at the first end of the junction, with one of the guide walls of the first guideway portion and contiguous, at the second end of the junction, with the guide wall of the second guideway portion spaced farthest from the third guideway portion, and a second guide wall portion extending between the other guide wall of the first guideway portion and the guide wall of the third guideway portion Spaced farthest from the second guideway portion, the second guide wall portion diverging from the first guide wall portion in the direction, along the second guide wall, from the junction first end to the second outlet, the roadway extending between the first and second guide wall portions; a first fixed rail structure, of L-shaped cross-sectional configuration, extending along the second guide wall portion from the second end of the junction to a location spaced from the first end of the junction, the first, fixed rail structure having a horizontal portion and a vertical portion comprising a first guide rail portion projecting downwardly toward the roadway and extending alongside the second guide wall portion at a constant height above the roadway, the first guide rail portion having a guide surface substantially perpendicular to the roadway, continuous along the length of the first guide rail portion, facing the second guide wall portion, and spaced from the second guide wall portion by a constant predetermined distance, the first guide rail portion being spaced from the first guide wall portion by a distance at least as great as the spacing between the guide walls of the guideway portions; a second, fixed rail structure, of L-shaped cross-sectional configuration, extending along the first guide wall portion from the second end of the junction to a location spaced from the first end of the junction by a distance greater than the distance between the junction first end and the first rail structure, the second, fixed rail structure having a horizontal portion and a vertical portion, comprising a second guide rail portion, projecting downwardly toward the roadway and extending alongside the first guide wall portion at a constant height above the roadway, the second guide rail portion having a guide surface substantially perpendicular to the roadway, continuous along the length of the second guide rail portion, facing the first guide wall portion, and spaced from the first guide wall portion by a constant distance equal to that between the first guide rail portion and the second guide wall portion, a single moveable rail structure of L-shaped cross-sectional configuration pivotally supported adjacent the second guide wall portion and between the second fixed rail structure and the first end of the juncture, the moveable rail structure having a horizontal portion and a vertical portion, comprising a third guide rail portion, projecting downwardly toward the roadway, the third guide rail portion having first and second ends and first and second, oppositely facing guide surfaces each substantially perpendicular to the roadway, the first guide surface of the third guide rail portion facing the first guide wall portion, the moveable rail structure being pivotable, about a rotational axis substantially perpendicular to the roadway and spaced between the first and second ends of the moveable rail structure, between a first position, in which the second end of the third guide rail portion is contiguous with the second guide rail portion and in which the first guide surface of the third guide rail portion is equidistant, along its length, from the first guide wall portion, and a second position in which the first end of the third guide rail portion is positioned immediately adjacent the first guide wall portion and in which the third guide rail portion second end is spaced, from the first guide wall portion, beyond the second guide rail portion and in which the distance between the second guide wall portion and the second guide surface of the third guide rail portion, along a line perpendicular to the second guide wall portion and intersecting the second end of the third guide rail portion, is substantially equal to the distance between the left and right guide walls of the guideway portions; first guide rail following means, mounted on vehicle, for moveably engaging the first guide surface of the third guide rail portion, and subsequently, the guide surface of the Second guide rail portion, upon the vehicle passing through the junction from the junction first end when the moveable rail structure is in its first position and, upon the moveable rail structure alternatively being in its second position, for moveably engaging the second guide surface of the third guide rail portion and diverting the vehicle toward the second guide wall portion; and second guide rail following means, mounted on the vehicle, for movement engaging the guide surface of the first guide rail portion and guiding the vehicle alongside the second guide wall portion and onto the third portion of the guideway upon the vehicle being diverted toward the second guide wall portion.
 28. The switching system of claim 27, the vehicle having means for moveably engaging the guide walls for guiding the vehicle along the guideway, the means for moveably engaging the guide walls including left and right follower structures adapted to ride against respective ones of the guide walls, the first and second guide rail following means being mounted on respective ones of the left and right follower structures.
 29. The switching system of claim 28, wherein the first and second guide rail following means respectively comprise first and second guide rollers rotatable about respective axes substantially perpendicular to the roadway, each guide roller projecting upwardly from the respective follower structure upon which it is mounted, the first guide roller being positioned in horizontal register with the second and third guide rails, and the second guide wheel being positioned in horizontal register with the first guide rail.
 30. In a transportation system employing at least one vehicle adapted to travel along a guideway, the system having a guideway junction having a first end communicating with a first portion of the guideway and a widened, bifurcated, second end communicating with second and third, mutually diverging portions of the guideway, a switching system comprising: guiding means, comprising a single moveable guide rail positioned adjacent the first end of the junction and pivotable about an approximately vertical axis between first and second positions, having a first guide surface operative for constraining a vehicle from turning toward the third guideway portion upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its first position, the guiding means further having a second guide surface operable for guiding a vehicle toward the third guideway portion upon the vehicle entering the junction from the junction first end when the moveable guide rail is in its second position; another guiding means comprising structure immovably positioned between the movable guide rail and the second guideway portion and operative for guiding a vehicle through the junction and onto the second guideway portion upon the vehicle being constrained by the first-mentioned means from turning toward the third guideway portion; and yet another guiding means comprising structure immovably positioned between the first end of the junction and the third guideway and operative for guiding the vehicle through the junction and onto the third guideway portion upon the vehicle being initially guided toward the third guideway portion by the first-mentioned guiding means. 